1. Field of the Invention
The present invention relates to cooling beds and particularly to cooling bed plates having a roller insert for supporting a heated object during cooling.
2. Background Art
Cooling bed plates are typically used in foundries and steel mills for supporting large, heavy billets or castings as they cool. Historically, cooling bed plates were large, heavy grids made up of a series of longitudinal rail members with interconnecting transverse members providing structure. Large billets to be cooled were placed on the cooling bed plates. In order to move the billets, they would either have to be lifted or skid across the grid surface.
There have been numerous efforts over the years to provide cooling bed plates with rollers so that objects can be transferred across an aligned series of cooling bed plates. The manufacturing of cooling bed plates having rollers is not a simple nor easy task. The roller assemblies must be capable of withstanding high loads and high temperatures in a steel mill. It is not uncommon to place steel billets on a cooling bed plate while the steel is in the 1400xc2x0 F. range. These high temperatures cause corrosion and lubrication problems for the rollers and associated bearings. When the cooling bed plate is used to support ferrous materials such as steel, it is common to lift the cooled steel billets off of the cooling bed plate using a magnetic crane. The rollers, if formed of a magnetic material, tend to lift with the magnet necessitating that the rollers be physically constrained in a vertical direction.
Suppliers in the past have manufactured roller insert assemblies for use in retro fitting cooling bed plates not initially provided with rollers. These systems tend to be complex, cumbersome and are susceptible to heat induced corrosion. It is an object of the present invention to provide a simple, reliable, low cost roller insert for cooling bed plates.
The cooling bed plate for use with the present invention is made up of a series of spaced apart longitudinal members, and a plurality of spaced apart transverse members which collectively define an array of pockets. A plurality of roller assemblies are installed in a cooling bed plate. Each roller assembly includes at least one roller which is pivotal about an axis, an axle cooperating with the roller provided with two end portions located opposite axial ends of the roller and a pair of bearing supports sized to fit within a pair of transversely aligned U-shaped cut out notches formed in a pair of spaced apart longitudinal members. A bearing is mounted within each of the bearing supports for pivotally receiving an axle end portion. The bearings are oriented at a height relative to the longitudinal members to orient the upper surface of the roller at a selected height above the cooling bed plate in order to provide rolling support for a heated, generally planar object positioned thereunder during cooling. Preferably, the bearings and bearing supports each contain a plurality of corresponding radial slots fitted with roll pins, to prevent rotation of the bearings within the bearing supports. Preferably, the bearings are made of a graphite material capable of withstanding the high heat and load experienced in a cooling bed plate environment. Ideally, the roller assembly will also include a retainer for vertically retaining the bearing supports within the U-shaped cut-out notches formed in the longitudinal members.